1. Field of the Invention
The present invention relates generally to shutoff valves and, more specifically, to a pressure activated shutoff valve that will maintain a base pressure in a pressurized system thereby maintaining a predetermined critical state to prevent crystallization of a liquified gas, in this case carbon dioxide from reverting to a solid state (dry ice). Furthermore, the present invention provides a manual cut-off switch to sever gas service to remote dispensing modules.
2. Description of the Prior Art
There are other valve devices designed for pressurized systems. Typical of these is U.S. Pat. No. 1,243,068 issued to Humphrey on Oct. 16, 1917.
Another patent was issued to Briggs on Jun. 27, 1967 as U.S. Pat. No. 3,327,521. Yet another U.S. Pat. No. 4,409,817 was issued to Edwards, Jr. on Oct. 18, 1983 and still yet another was issued on Nov. 22, 1994 to Ueda, et al. as U.S. Pat. No. 5,365,772.
Another patent was issued to Ewing, et al. on Mar. 6, 2001 as U.S. Pat. No. 6,196,056. Yet another U.S. Pat. No. 6,286,362 was issued to Coffman, et al. on Sep. 11, 2001. Another was issued to Sienel on Jul. 16, 2002 as U.S. Pat. No. 6,418,735 and still yet another was issued on Dec. 9, 2003 to Abbel as U.S. Pat. No. 6,658,920.
Another patent was issued to Hayakawa on May 16, 1995 as Japanese Patent No. JP7125796. Yet another Japanese Patent No. JP2002037394 was issued to Hosokawa on Feb. 6, 2002. Another was issued to Schneider on Oct. 24, 2002 as German Patent No. DE 10104207.